We request funds to purchase an MMI CellCut Laser Microdissection (LM) system. The new instrument will be housed within the Program in Membrane Biology (PMB) Microscopy Core at the Massachusetts General Hospital (MGH) in the new Charles River Plaza (CRP) research building that will be completed in the summer of 2005. The mandate of this core facility is to provide access to a full range of techniques using microscopy and imaging to individual research groups, 3 PHS funded Centers and 3 new Thematic Centers within the MGH community. Over the past three years, the Core has developed considerable expertise in LM techniques and is now in an excellent position to offer this procedure as a routine service to its wide user base. The two major reasons for this application are: 1) To provide critically needed LM time to support increasing demand from current and new users who will be located in the new CRP building - the requested system would be the only laser microdissection system in this building. Several investigators who will relocate to CRP currently use an older LCM system that will remain in the "MGH-East" facility,1.5 miles away (across the Charles River), close to the MGH main campus, in which our Core is currently located. Other PMB Core equipment that was purchased with PHS and private funds, as well as all PMB scientific faculty and our 3 Core technologists, will move into the new CRP building next year. Other investigators from the main MGH campus will also relocate to the new CRP building. A new, on-site LM system is, therefore, essential for many PHS funded investigators to be able to continue their ongoing work using this technique as well as to provide LM capability to new users. 2) Provide access to the new "laser cutting" technology that has significant advantages over the original "laser capture" technique. Briefly, the cutting technique provided by the MMI system allows one to sample cells from non-fixed, non-dehydrated sections. This means that soluble fluorescent molecules such as GFP can be expressed in cells as highly specific markers (in transgenic animals, for example) - such markers are removed from non-fixed samples by ethanol/xylene dehydration. Since the PMB Core was founded in 1986, it has become an central part of the MGH/HMS medical research community. Over 55 PHS-funded PIs within the HMS/MGH and in other institutions have used the facility in the past 24 months. The Core has an ongoing quest to constantly improve and upgrade Core facilities in support of its user base. Providing laser microdissection access and expertise to the MGH research community will be an important part of our mission and bridges the gap between pure microscopy studies and functional genomics that take advantage [unreadable] [unreadable] [unreadable]